Direct answer
Most dripping faucets are caused by a worn washer, O-ring, or cartridge. The fix is replacing the faulty part, which costs a few dollars and takes 30 to 60 minutes depending on your faucet type. The job requires basic tools and no plumbing experience, but you do need to identify your faucet type before you start.
Why faucets drip
Water drips when something inside the faucet is no longer creating a watertight seal. In most residential faucets that comes down to a rubber washer or O-ring that has worn down over time, or a cartridge that has failed. The constant pressure of water against these parts wears them out eventually. Fixing the drip means replacing whichever part has failed.
Identify your faucet type first
The repair process differs depending on what kind of faucet you have. There are four common types in residential homes.
Ball faucets have a single handle that rotates over a rounded cap. Common on kitchen sinks. They contain a ball mechanism with several small parts including springs, seats, and O-rings, any of which can fail.
Cartridge faucets have a single or double handle that moves up and down or side to side. Inside is a cartridge that controls water flow. This is one of the simpler repairs since the fix is usually pulling the old cartridge and pressing in a new one.
Ceramic disc faucets have a single lever over a wide cylindrical body. They use two ceramic discs that rarely wear out but can fail if grit gets inside. Often the fix is cleaning rather than replacing.
Compression faucets are the oldest type, with two separate handles that you tighten down to stop water flow. Very common in older homes. The rubber washer at the bottom of the stem wears out and is the usual cause of dripping.
If you’re not sure what type you have, turn off the water, take the handle off, and look at what’s inside. A quick image search of what you find will confirm the type.
What you need
Adjustable wrench, flathead and Phillips screwdrivers, replacement parts for your faucet type, plumber’s grease, and a towel or small bucket to catch water. For cartridge faucets, needle-nose pliers help with removing the cartridge clip.
Take photos as you disassemble. Faucet internals have an order and orientation that matters when you reassemble.
Step one: Shut off the water supply
Under the sink there are two shut-off valves, one for hot and one for cold. Turn both clockwise until they stop. Then turn the faucet on to release any pressure and drain the remaining water in the line. Put the drain stopper in place or lay a towel in the sink to catch any small parts that might fall.
Step two: Remove the handle
Most handles are held on by a screw hidden under a decorative cap on top of the handle. Pop the cap off with a flathead screwdriver, remove the screw underneath, and pull the handle straight up or toward you. Some handles are snug and need a gentle side-to-side wiggle to come free. Don’t force it.
Step three: Access and replace the faulty part
This is where the process differs by faucet type.
For a compression faucet, unscrew the packing nut with your wrench and pull out the stem. At the bottom of the stem is a rubber washer held by a brass screw. Replace the washer with one that matches the size exactly. If the seat the washer presses against feels rough when you run a finger over it, it may need resurfacing with a seat wrench or replacement, which is what causes the washer to wear out prematurely.
For a cartridge faucet, remove the retaining clip at the top of the cartridge with needle-nose pliers, then pull the cartridge straight out. Take it to a hardware store to match the replacement exactly, or note the faucet brand and model and buy the correct replacement cartridge. Press the new one in the same orientation as the old one. Orientation matters. If you install it backwards the hot and cold will be reversed.
For a ball faucet, purchase a repair kit for your faucet brand rather than trying to source individual parts. The kit includes all the small components, springs, seats, O-rings, and a new ball if needed. Replace everything in the kit while you have it open. Trying to identify and replace only the one failed piece in a ball faucet is rarely worth the effort since the other parts are similarly worn.
For a ceramic disc faucet, remove the cylinder and take out the ceramic discs. Clean them with white vinegar and a soft cloth to remove mineral deposits. Inspect for cracks or chips. If the discs are intact, cleaning usually solves the drip. If cracked, replace the cylinder as a unit.
Step four: Reassemble and test
Apply a thin coat of plumber’s grease to any rubber parts before reassembling. This extends the life of washers and O-rings significantly. Reassemble in reverse order, hand-tighten everything first, then snug with the wrench. Don’t overtighten.
Turn the shut-off valves back on slowly. Turn the faucet on and let it run for a minute, then turn it off and watch for dripping. Check under the sink as well to make sure the supply line connections are dry.
If the drip continues
A drip that persists after replacing the washer or cartridge usually points to one of a few things. The replacement part may not be the right size or model. The valve seat inside the faucet body may be worn or corroded, which prevents any washer from sealing properly against it. Or on older faucets, the faucet body itself may be corroded in a way that parts alone can’t fix.
A worn valve seat can be resurfaced with a seat wrench for a few dollars, or the seat can be replaced on faucets where it’s removable. If the faucet is old and the body is in poor shape, replacement is often the more practical path than continued repair.
When to call a plumber
A standard faucet repair is well within DIY range. Call a plumber if you find corrosion or damage at the supply line connections under the sink, if the shut-off valves under the sink won’t close fully and you need to shut off water at the main, or if the faucet body itself is cracked or corroded beyond what parts can address.
A dripping faucet that goes unrepaired wastes more water than most people expect. A faucet dripping once per second wastes roughly 3,000 gallons per year. The repair is worth doing promptly.
